PEG derivatized lipids are used to increase the circulation time of liposomes and lipid nanoparticles (LNPs) in vivo. The hydrophilic PEG chains decrease interactions with the reticular-endothelial system and increases the size of the particles both of which result in lowered clearance rate from the body. The amino group can be reacted with acidic groups or NHS-esters forming a stable amide-bond.
